DESCRIPTION (Adapted from abstract): Multidimensional NMR methods will be used to investigate the mechanisms of nucleic-acid recognition by two key eukaryotic transcription factors, the Wilms tumor suppressor protein (WT1) and transcription factor IIIA. These both contain ubiquitous zinc finger motifs and bind both DNA and RNA. The solution structure and dynamics of DNA complexes formed by the +KTS (Lys-Thr-Ser) and -KTS isoforms of WT1 will be determined to obtain insights into the molecular basis by which alternate splicing is able to modulate DNA binding and specificity. The solution structure and dynamics of the complex between zinc fingers 4 - 6 of TFIIIA and a 55-nucleotide RNA molecular encompassing the TFIIIA-binding core region of Xenopus 5S RNA will be determined to provide insights into the molecular basis by which the zinc finger motif can recognize both RNA and DNA.